nondeterministic failure in ` byte immutable copyTo!` interpreter test?

[aryairani]

See https://github.com/unisonweb/unison/actions/runs/7925721522/job/21640053744#step:16:569

[aryairani]

Just going through some old tickets. Any ideas about this? @dolio

[dolio]

Not off hand. Does it still happen sometimes?

[dolio]

Never mind. I do see the problem.

In the tests, checkBytesMI and checkBytesMM are wrong. The recursive call is:

checkBytesMI src larr rarr (l - 1)

But l is the value that was read out of the array, not the index. And the non-determinism is because the array is bigger than what we write to it in some of the tests, so sometimes it has random bytes that point you out of bounds.

[dolio]

Pushed an update to those functions.